植物生态学报 ›› 2021, Vol. 45 ›› Issue (6): 594-605.DOI: 10.17521/cjpe.2020.0372

• 研究论文 • 上一篇    下一篇

阔叶红松林不同演替阶段凋落物产量及其稳定性的影响因素

孙浩哲, 王襄平*(), 张树斌, 吴鹏, 杨蕾   

  1. 北京林业大学生态与自然保护学院, 北京 100083

Abiotic and biotic modulators of litterfall production and its temporal stability during the succession of broad-leaf and Korean pine mixed forest

SUN Hao-Zhe, WANG Xiang-Ping*(), ZHANG Shu-Bin, WU Peng, YANG Lei   

  1. College of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
  • Received:2020-11-11 Accepted:2021-03-19 Online:2021-06-20 Published:2021-09-09
  • Contact: WANG Xiang-Ping
  • Supported by:
    National Key R&D Program of China(2017YFC0503901);National Natural Science Foundation of China(31870430)

摘要:

凋落物产量是生态系统净初级生产力的重要组分, 也是连接地下与地上生态过程的关键环节。但在森林演替进程中, 生物多样性、林分因子、功能性状如何共同影响凋落物产量及其时间稳定性, 其机理有待进一步研究。该文在阔叶红松(Pinus koraiensis)林分布的北界黑龙江胜山保护区, 选择从演替早期到红松原始林的4个演替(或发育)阶段, 连续3年测定凋落物产量, 以3年凋落物产量的变异系数的倒数(1/CV)反映其稳定性。采用层次划分和变异分离等方法研究林分因子(最大树高、胸径、胸高断面积、林冠空隙度)、群落水平功能性状(叶碳、氮含量及比叶面积)和乔木多样性(物种、功能、谱系多样性)对凋落物产量及其稳定性的相对作用大小。结果表明, 演替早期凋落物产量显著低于后3个演替阶段, 从演替中期至演替晚期凋落物产量无显著差异。凋落物产量的稳定性随演替进展显著提高。对变量重要性的评价表明, 凋落物产量主要受林分因子(最大树高、胸高断面积、林冠空隙度)和性状(叶碳含量)的影响, 物种丰富度也起一定作用; 而功能多样性对于凋落物稳定性的作用最大, 其次是林分因子(如最大胸径)。生物多样性对凋落物产量的独立解释力仅为0.41%, 而对其稳定性的独立解释力为33.12%, 说明多样性对凋落物稳定性有着独立于林分因子、性状之外的重要作用。同时, 林分因子、生物多样性、性状之间存在较强的协同作用(最高达53.8%), 说明这3种因素共同作用于凋落物产量及其稳定性。研究结果表明, 森林的恢复演替不仅能提高森林生产力, 还可有效提高生态系统稳定性, 因此, 保护原始林及促进森林恢复演替是提高生态系统功能的有效手段。

关键词: 凋落物产量, 稳定性, 生物多样性, 林分因子, 演替, 功能性状, 阔叶红松林

Abstract:

Aims Litterfall is an important component of ecosystem net primary productivity, and a key link between above- and below-ground carbon processes. However, it remains unclear how biodiversity, stand factors and functional traits work together in affecting litterfall production and its temporal stability during forest succession.

Methods We measured litterfall production for three years in plots from four successional stages of broad-leaf and Korean pine (Pinus koraiensis) mixed forests, at the northern limit of Korean pine forest in the Shengshan Reserve of Heilongjiang. Functional traits (leaf carbon and nitrogen contents, specific leaf area) were measured to quantify functional diversity and community weighted mean (CWM) of traits. Tree diameter and height, total basal area (TBA) and gap fraction were measured to quantify stand structure. We used hierarchy partitioning analysis and variance partitioning to evaluate the relative effects of stand factors, community level traits, and (species, functional and phylogenetic) diversity on annual litterfall production, and its temporal stability (= 1/coefficient of variation for annual litterfall production).

Important findings Litterfall production was significantly lower in the early successional stage, but did no vary from the middle to late successional stages. The litterfall stability increased continuously with forest succession. The variable importance of multivariate models also suggest that, the litterfall production was mainly affected by stand factors (e.g. height, TBA, gap fraction) and functional traits (leaf carbon content), with species richness also playing a role. For stability of litterfall production, however, functional diversity was the strongest predictor, followed by stand factors (such as maximum tree diameter). The independent effect of biodiversity on litterfall production was only 0.41%, but was as much higher (33.12%) for temporal stability of litterfall, suggesting that biodiversity have an important influence on litterfall stability that is independent of stand factors and traits. There was also a strong joint effect (up to 53.8%) among the stand factors, biodiversity and functional traits, indicating that these factors collectively affect litterfall production and its stability. Our results suggest that forest succession not only increases forest productivity but also improves ecosystem stability. Therefore, protecting primary forests and promoting forest restoration are effective ways to improve ecosystem functions.

Key words: litterfall production, stability, biodiversity, stand factors, succession, functional traits, broad-leaf and Korean pine mixed forest